1. Field of the Invention
The present invention relates to an air conditioner for an automobile, particularly preferable for an air conditioner used in an electric automobile driven by a driving motor.
2. Description of Prior Art
Although a conventional air conditioner of an engine-driven automobile is generally driven by an engine, an air conditioner of an electric automobile including a hybrid automobile, is driven by electricity similar to an air conditioner for household use. Therefore, although according to the conventional engine-driven automobile, heating can be carried out by utilizing waste heat at a high temperature, according to the electric automobile, waste heat at a high temperature by the engine is not provided normally and therefore, it is necessary to carry out heating by a heat pump using a refrigeration cycle similar to an air conditioner for household use.
In such an air conditioner of an electric automobile, as disclosed in Japanese Patent Laid-Open No.368221/1992, there is provided a constitution having a heat pump heating and cooling apparatus constituted by a compressor, an exterior heat exchanger, an exterior fan, an expansion valve, an interior heat exchanger, an interior fan and a four-way switch valve, an axle driving motor, a first air flow path introducing air having passed through the driving motor, a second air flow path directly introducing outside air and an apparatus of switching or opening and closing the two air flow paths in order to enable effectively utilizing waste heat of the axle driving motor and enabling defrosting the exterior heat exchanger in a heating mode of the heat pump.
According to the conventional technology, in heating by the heat pump, the first air flow path is opened and the second air flow path is closed, thereby, the outside air is heated by the waste heat of the driving motor and reaches the exterior heat exchanger and therefore, the waste heat of the driving motor can be utilized for heating by the heat pump. Further, when frost is formed and developed at the exterior heat exchanger depending on conditions of temperature and humidity of the outside air in heating, the heating cannot be carried out and therefore, defrosting is carried out by guiding gas at a high temperature delivered from the compressor of the refrigeration cycle to the exterior heat exchanger to thereby heat the exterior heat exchanger in a state in which the first air flow path is also closed and air does not flow through the exterior heat exchanger.
According to the above-described conventional technology, the waste heat of the driving motor is utilized in heating by the heat pump by making the outside air flow through the exterior heat exchanger after passing through the surrounding area of the driving motor and therefore, the driving motor must be arranged on the upstream side of the exterior heat exchanger and arrangement of the driving motor in a motor chamber is restricted. When the driving motor is arranged at a side or a rear side of the exterior heat exchanger in order to improve the restriction, there poses a problem that a shape of a duct constituting the air flow path becomes complicated and expensive and a cooling wind amount can not be provided sufficiently.
Further, according to the conventional technology, heat exchange is carried out between an outer peripheral face of the driving motor and outside air and therefore, there poses a problem that the heat exchange efficiency is low and waste heat of the driving motor cannot be utilized sufficiently. When the outer peripheral face of the driving motor is provided with fins in order to increase the heat exchange amount between the driving motor and the outside air, there poses a problem that an outer diameter of the driving motor is increased and performance of containing the driving motor is deteriorated.
Further, according to the conventional technology, there is not a description with regard to a case in which in heating by the heat pump, when snow or rain falls, snow or rain reaches the exterior heat exchanger by air flow caused by travel motion of the automobile and frost formation on the exterior heat exchanger is accelerated or the frost is frozen and heating is hampered.
Further, according to the conventional technology, a consideration is given only to utilizing the waste heat of the motor for driving the automobile and there is not a description with regard to utilizing waste heat of an inverter constituting a motor driving power source along with the driving motor and promotion of cooling function of the both.
It is a first object of the invention to provide an air conditioner for an automobile removing restriction on arrangement of electric apparatus, capable of achieving small-sized and light-weighted formation by promoting cooling capacity of the electric apparatus by a cooling fluid cooled by a radiator by an inexpensive constitution of flowing air to the radiator by an exterior fan in heating operation and capable of definitely defrosting the exterior heat exchanger by closing an air flow path of the exterior heat exchanger in heating operation.
It is a second object of the invention to provide an air conditioner for an automobile removing restriction on arrangement of a driving motor and a motor driving power source and capable of achieving small-sized and light-weighted formation by promoting cooling capacity of the driving motor and the motor driving power source by a cooling fluid in heating operation.
It is a third object of the invention to provide an air conditioner for an automobile removing restriction on arrangement of electric apparatus, capable of achieving small-sized and light-weighted formation by promoting heating capacity by effectively utilizing waste heat in heating operation and promoting cooling capacity of the electric apparatus by a cooling fluid, capable of definitely defrosting an exterior heat exchanger by closing an air flow path of the exterior heat exchanger in heating operation and capable of promoting cooling function by flowing wind to a radiator and the exterior heat exchanger in parallel with each other in a cooling operation.
As first means of the invention in order to achieve the first object, there is provided an air conditioner for an automobile used for an electric automobile comprising a driving motor for driving the automobile and a motor driving power source for driving the driving motor, the air conditioner comprising, a refrigeration cycle formed by connecting an electrically driven compressor, an exterior heat exchanger, a pressure reducing apparatus, an interior heat exchanger and a four-way switch valve, an exterior fan for flowing outside air to the exterior heat exchanger, and an interior fan for flowing inside air to the interior heat exchanger, further comprising a radiator connected to cool a heat generating electric apparatus such as the driving motor or the motor driving power source via a cooling fluid, wherein the radiator is arranged on an upstream side of the exterior heat exchanger in an air flow path of the exterior fan and an opening and closing apparatus for opening and closing an air flow path of the exterior heat exchanger is provided.
According to second means of the invention for achieving the second object, the radiator connected to cool both of the driving motor and the motor driving power source via a cooling fluid is arranged in an air flow path by the fan.
According to third means of the invention in order to achieve the third object, in an air conditioner for an automobile, there is provided a radiator connected to cool a heat generating electric apparatus such as the driving motor or the motor driving power source via a cooling fluid, there are provided a first air flowing duct arranged with the exterior heat exchanger and a second air flowing duct arranged with the radiator and there is provided an opening and closing apparatus for opening and closing the first and the second air flowing paths such that air flows to the radiator and the exterior heat exchanger in this order in heating operation and the air flows to the radiator by closing an air flow path of the exterior heat exchanger in defrosting operation and the air flows to the radiator and the exterior heat exchanger in parallel with each other in a cooling operation.